Dan Carter, the New Zealand captain, described the circumstances surrouding his fateful injury as the 'craziest day of my life'. Photograph: Bogdan Cristel/Reuters

It was a good day for a farewell, with rain lashing in off the Hauraki Gulf. So much of this World Cup is about moving on, about spring heading towards summer, but this was about going the other way, away from Auckland and across the mist-shrouded bridge into Takapuna, where the All Blacks were staying.

Spencer on Byron is a troubled hotel. Here the French had stayed; say no more. Here, Dan Carter was packing his bags. And here was a chance to linger on his misery. He tore the left adductor muscle in his groin on striking his fourth place-kick at the end of last Saturday's captain's run – his run, for he was due to lead the team the next day. It ruined what he called the "craziest day of my life". Captain of his country one moment, out of the World Cup the next.

It was obviously his last kick, but he had always intended to take only four practice shots at goal, instead of his normal 20. "Nothing was different," he said. "It was my normal routine, except I had decided to do just the four. I've kicked thousands of balls and ... I don't know what happened. Something popped and suddenly I was on the ground in agony."

Alongside Carter sat Steve Hansen, assistant coach of the All Blacks. He described what happened next. "Ted [the head coach Graham Henry] went into the sheds [changing room] and told the guys. He said Dan had done a groin and wouldn't be playing tomorrow."

Or, as it turned out, anytime in the next few months. The funny thing was that Carter, two days later at this farewell, was smiling. The national mood had turned the colour of the weather, utterly glum, but the victim was even laughing. He hadn't when it happened: "I was angry. I was a bit different behind closed doors on Saturday. I spoke to a lot of people close to me. It was a tough night."

He would not be staying with the team. "That's how it goes. You have to bring in a replacement [Aaron Cruden], and I lose my World Cup accreditation. I'll be popping in every now and again. Ted's going to give me a few clips on the opposition and ask me what I think. I'll be going to the games. I'm not the best spectator, but the beauty of sitting out there is you can maybe see things you can't when you're playing. I'll relay anything I see to the players."

There was nothing really beautiful about any of that, but the smile and the slightly forced spin were part of the next phase. "The team must move on now. I have. Everyone should. I'm here to talk to you guys here today, and that's the end of it."

Picking up the pieces became the theme. "All sportspeople know that this (injury) is a possibility," said Hansen. "Many have had their moment taken away from them, and it's not easy for them to come here and talk to you. But you've got to move on. I'll tell you one thing. Colin Slade [Carter's stand-in on Sunday against Canada] doesn't have to be Dan Carter. He has to be Colin Slade. The rest of the team have to be a little bit better everywhere. Adversity can make you a better person. Maybe Dan Carter will be a better bloke – and he's a top bloke now."

This was only to be expected. The alternative was to let the national mood seep under the door with the driving rain, and that was hardly going to be allowed. But ask anyone here who was the last person the All Blacks could afford to lose and they would all reply: Dan Carter.

It is not just that he is the leading points scorer in the history of rugby, the consummate strategist and the catalyst for everyone else's glowing performances; it is also that he has always been so important that nobody else has ever been given a run in the No10 shirt.

Nick Evans and Luke McAlister were given a go, but so limited were their opportunities that they went overseas and became ineligible for All Black selection. Piri Weepu and Slade from the current squad have both had a bash at filling the void whenever Carter has been missing but neither has truly fitted the bill. Cruden, from Manawatu, young and very promising, may one day soon be the one to fill Carter's boots, but not yet.

For all the encouraging noises that the wounded player and the team that he leaves behind were obliged to make, there was no hiding a sense of foreboding at his farewell session. All those present knew what three sets of World Cup opponents know, that the All Blacks without Carter are not the same. When he went down, New Zealand went down and not many on this bleak day felt like bouncing back to their feet.